The Rally Expansion Add-on for Forza Horizon has 10 achievements worth 250 gamerscore.
Win a Horizon Rally.
Get a total of 1609 metres of air in Horizon Rally events.
Obtain your first Horizon Rally car.
Complete your first Horizon Rally stage.
Become the Horizon Rally Champion.
Win a Rally stage on Hard opponent difficulty without using automatic shifting or the Driving Line.
Complete 5 Horizon Rally events in Rivals mode.
Win 10 Horizon Rally stages in online multiplayer.
Win a Horizon Rally stage without crashing or using rewind.
Purchase all five Horizon Rally cars.